污水沉降罐伴热盘管传热特性与影响因素分析

Analysis of Heat Transfer Characteristics and Influencing Factors of Sewage Settling Tank with Heating Coils

在沉降罐液位举升与收油过程中,采用稳-瞬态相结合的全过程传热计算方法,建立了污水沉降罐稳态-瞬态传热温度场分析三维有限元耦合模型,对污水沉降罐和伴热盘管全运行过程传热特性进行分析,得到沉降罐与伴热盘管的温度分布。结果显示:在收油过程中,各圈盘管温度由进水侧向出水侧逐渐降低,盘管环向温降在0.1℃/m左右,盘管同一角度径向温降在每圈1℃左右;通过研究不同影响因素可知,进口温度、环境温度的升高以及盘管直径的增大都能有效提高伴热盘管传热特性,而保温层厚度的增大和进口流速的提高对伴热盘管传热特性影响很小,影响因素敏感程度排序为进口温度>环境温度>盘管直径>保温层厚度>进口流速。

In liquid level lifting and oil recovery process of the settling tank and based on the steady-transient heat transfer calculation method,a three-dimensional finite element coupling model for the steady-transient heat transfer and temperature field analysis of the sewage settling tank was established to analyze heat transfer characteristics of the whole operation process of the sewage settling tank and the heating coils so as to obtain temperature distribution of the settling tank and the heating coils.The results show that,in the oil recovery process,the temperature of each coil decreases gradually from the inlet side to the outlet side,and the coil circumferential temperature drops at about 0.1℃/m and the coil’s radial temperature drops at about 1℃/coil at the same angle.Comparing different influencing factors indicates that,as for the increase of inlet temperature,both ambient temperature and coil diameter can effectively improve heat transfer characteristics of the heating coils while increase of the thickness of the insulation layer and that of the inlet flow rate have little effect on the heat transfer characteristics of the heating coils.The sensitivity rankings of the influencing factors are as follows:inlet temperature>ambient temperature>coil diameter>insulation layer thickness>inlet flow rate.